grid: optical illusion?

function setup() {

  createCanvas(windowWidth, windowHeight);

  background(230);

  noFill()

  stroke(60);

  strokeWeight(1)

  noLoop();

}

​

function draw() {

  const numCols = 30;

  const spacing = width / numCols;

  const numRows = floor(height / spacing);

​

  for (let xGrid = 0; xGrid <= 30; xGrid++) {

    for (let yGrid = 0; yGrid <= numRows + 1; yGrid++) {

​

      const x = xGrid * spacing;

      const y = yGrid * spacing;

​

      circle(x, y, random(5, spacing))

    }

  }

​

}